Abstract: A supporting bracket is secured to the housing of a tightener for a load binder used with a truck. The bracket extends outwardly in overlapping engagement with the upper surface of the inwardly projecting flange of a truck bed side rail and is slidable along the rail. A sprocket and ratchet are rigidly mounted on a shaft rotatably mounted in the housing, and a pawl connected to the housing engages the ratchet. When the shaft is rotated a sprocket chain, one end of which is fastened to the load binder, is wound on the sprocket to tighten the load binder. A shock absorber and tension-indicating block is disposed between the housing and the side rail.